Actuating device



Feb. 9, 1960 R. w. MCANALLY ACTUATING "DEVICE 2 SheetsQ-Sheet 1 FiledJuly 31. 1956 INVENTOR. Ras/snr m m ANALLY ,"Illlll R. W. MCANALLYACTUATI-NG DEVICE Feb. 9,' 1960 2 Sheets-Sheet 2 Filed July 3l. 1956INVENTOR. ROBERT IM McA/VALLY Il f .M

i TT /VEY nit-e Stts i p ACTUATING DEVICE Robe'rtlWaMcAnally, FortWorth, Tex', assignorto Gen'- eral Dynamics Corporation, SanDiego,lCalif.,-a Acorporation of Delaware i Y Application July 31, 1956,Serial No. 601,299

6 Claims. (Cl. 244-121)- Certain aircraft' components, such as' the`aircraft canopy, door, or landing gear, must be repeatedly operated,land, by reason of their size and4 weight, such opera-tion is generallythrough power actuators' or, at the least, manually with the assistanceof power actuators.v An example of the latter is found inthe opening andclosing of an aircraft canopy. "This manual opera'-` tion is assisted bythe usual provision of a pneumatic Or'hydraulic actuator cylinder forcounterlbala'ncing the weight of the canopy, and by this means anaircraft crew member can easily manage the opening or closing operationduring entrance and exit. i

vIn certain emergency situations, as, for example, where there has beena failure `of the landing gear hydraulic system, or where jettisoningofan aircraft canopy or hatch' is necessary to permit escape, there hasheretofore been provided a sep-arate emergency actuator foraccomplishing the emergency function. This actuator, generally anexplosive or pneumatic cartridge type,` Was duplicative of the poweractuators employed for normal operation of the aircraft components, andthe duplica-I tion of Vmechanism required undesirable increases in sizeand'weight of -theaircraft Accordingly, the present invention `providesa unique power lactuating device which embodies both a cartridgeactuated emergency mechanism and 'la fludor spring operated mechanismfo-r normal operating requirements. The invention is particularlyadapted to assistinachievingrelative movement between-the canopy "andfuselage of al'l'aircraft, and in jettisoning the canopyiinanemergencyfsituation. Thus, in a single devicelthereis providedacomposite structure capablek ofachievingboth the normal operation ofthe' canopy "and 'the'emergency operation-lof Ilthe canopy, eliminatingthe duplication of mechanisms required by the priorart' to accomplish'the sameresult. The space yand lweight therebyi'saved' are criticalitems in` aircraft, and the consequentl'advantages or'ther'presentVinvention will therefore'beapparentl" In addition, the provisionof'an-integral-cartri'dge achieves reliable "and immediate separation'orjettisoningofthe aircraftv canopy, and -in anheasily irlitiatedandl"quickly accomplishedaction; yas will ibe seen.v

ltifislto'fbe-understood, off'rcourse, that' the* direction of 'fthediscussion and-description hereini to aircraft .come po'neuts,andlaircraft canopiesin 1particular,- is nothin# tended to be klimitingsinceuhe fprfesent actuator -device is readily susceptible 'v of variousv applications-f' wherein there* is` required the combination Noffunctions and structures `Which-lis' afforded' by 'the devlit'ze'y ofAthe present 'ini vento'n:

Therefore, i-t is an object of 'thefipresent'invention'to' icc I providecounter-balanced relative movement between a liiieci member andavmovable member, andwhich isalsd adapted-to be 'actuated to effectquick and forciblemove'- mentof said movable member away from said fixedmember. A

A further object of the invention is to provide` an improved actuatingdevice which is `adapted not only to assis-t in etfecting raising andlowering of an aircraft canopy, but also is adapted to explo-sivelyVjettison the CaDQPY A still further object of the invention residesinthe provision of a unique composite actuator device that is easilyvcontrollable, relatively simple in operation, and reliable.

Other objects and features of the present invention will be readilyapparent to those skilled in the art from the following specificationand appended drawings wherein is illustrated a preferred form of theinvention, and in which: p

kFigure 1 is a partial perspective view o-f an actuator device of thepresent invention illustrated in connection with yan aircraft canopy;

Figure 2 is-a longitudinal view in cross section of the actuator deviceof Figure 1; v

Figure 3 is a view taken along III-III of Figure 2;

Y Figure 4 is a detail view in cross section taken along IV--IV ofFigure 2; and

'Figure 5 is a cut-away perspective View of a second embodiment of thepresent invention.

Referring now to the drawings, and in particular to Figures l and 2,there is illustrated an actuating device 11 which is adapted forconnection between the fuselage 12 of an aircraft and a usual hingedcanopy 13 of such aircraft, and which serves upon opening and closing ofcanopy 13 to counterbalance the weight thereof, and which also serves toforcibly eject or jettison canopy 13 in emergency situations. The mannerin which device 11 is secured to-fuselage 12 at its lower end and tocanopy 13 at its upper-end is not important to the present invention andtherefore such mounting arrangement ywill not be described in detailother than to note that the mounting is' pivotable. Further, canopy 13is pivotedlin the usual manner at its rearward endto fuselage 12-V athingeass'emblies-lll, and since the precise-construction of hinges 114and the manner of their interconnection between canopy-13 and fuselage12 is also not important to thepresent invention, va detaileddescription thereof will be omitted 'for brevity'. l

Actuating'device 11, whichis showninits extended position in Figure 1and in itsretracted position inFig? ure 2,y comprises, generally, anexternal cylinder or'body 15 which is pivotally carried by fuselage 12at a pair of trunnons 16, Figure 3; an internal vsleeve or cylinder17vwhich is slidable longitudinally within body 1s dur-4 ing emergencyoperation of device 11; a piston 18'long i tudinally slidable withininternal cylinder 17 lduring', normal opening'and closing of canopy 13;a cartridge'hold'er',

19l nested within the'right end (as viewed in Figure ofA internalcylinder 17; a conventional explosive carl tridge 21 carriedwithinholder 19; and a usual firing; pin 22 slidably` disposed within theright end of tbody: 15` and'in axial alignment with cartridge 21. At itslefty end actuating devicel 11 is providedA with` a cleviselef4 ment '23Ylwhicli'is provided with a pair of aligned open`" ings 24 for pivotalaccommodation of a bolt notishown) of themountih'g assemblyof canopy 13.Thus, actuati ing devicell is pivotally mountedat"trunnions"16"tofuselage 12, and at `-clevis 23 to`|canopy"13, and arranged',as"'illustrated-whereby lthe extensionl'of'piston 18 serves tlrais'ecanopy/"13 and converselyth'e retraction ofpiston ls'se'rvesf'tolowercanopy 13. In fadditiongifasfwillf'bei' coniapparentl/hereinafter, the-explosion-'oflcatridge acts to urge cartridge holder 19, internalcylinder 17 and piston 18 outwardly or to the left, as viewed in Figure2, thereby forcing canopy 13 upwardly, separating canopy 13 fromfuselage 12. Y

Main body 15 of actuating device 11 comprises, gen erally, alongitudinally extending sleeve element 25 whose inner surface serves ineffect as a cylinder rfor the piston action of internal cylinder 17during emergency ejection of cylinder 17, sleeve element 25 beingperipherally threaded to receive an internally threaded coll-ar 26; ahead or end portion 27 threadably secured to the right end of sleeveelement 25; and a collar 28 threadably secured to the left end of endportion 27. A plurality of sealing rings 29 are provided between thecomponents of body 15 to provide a fluid tight interconnectiontherebetween. Portion 27 is internally bored at its right end to form achamber 31 within Iwhich tiring pin 22 is slidable, and a port 32 isprovided adjacent thereto in portion 27 to alTord a means forintroducing fluid pressure within the right end of chamber 31 to therebydrive firing pin 22 to the left for the actuation or explosion ofcartridge 21.

Internal cylinder 17, which is slidable within body 15 during theejection operation, is of three part construction and includes a leftend portion 33 threadably secured to the left end of a sleeve 34 whichis normally held in locked or fixed relationship with respect to sleeveelement 25 of body 15 by a plurality of balls 35 carried within Valignedopenings provided `in sleeve element 25 and sleeve 34. It will beapparent that the provision of balls 35 normally prevents relativemovement between sleeves 25 and 34, and that ejection of internalcylinder 17 from body 15 cannot occur until balls 35 are moved out ofinterfering relationship therebetween. The third part of internalcylinder 17 is a housing element 36 which serves to enclose the greaterportion of cartridge holder 19, housing 36 being externally threaded atits open right end for threaded connection to internal threads providedon the right end `of `sleeve 34. Housing 36 eX- tends to the left inspaced relationship with sleeve 34 to form an annular chamber 37 withinwhich a skirt 38 of piston 18 is operable, as will be seen. Housing 36is closed at its left end so that the expanding gases of eX- plodingcartridge 21 will serve to act tliereagainst and drive internal cylinder17 to the left. A plurality of sealing rings 39 are provided, asillustrated, to elect a fluid tight relationship between the componentsof internal cylinder 17 and between cylinder 17, body 15, and cartridgeholder 19.

Cartridge holder 19 includes a skirt 50, which is slidably nested withinhousing 36, and an end portion 41 which is threadably secured to skirt50. End portion 41 is longitudinally slidable within the right end ofsleeve 34 and within a hollowed-out internal chamber 42 of end portion27, a portion of chamber 42 serving in eiect as an extension of thesleeve 34. In its left or locked position, end portion 41 serves tomaintain balls 35 in their locking positions, `and this locked positionof end portion 41 is normally maintained i through the bias of a helicalspring 40 carried within chamber 42, as illustrated, and acting againstend portion 41. It will be noted, however, that upon explosion ofcartridge 21 the expanding gases will act against end portion 41 anddrive it to the right within charnber 42 and against the bias of spring40, and out of locking position to permit balls 35 to drop inwardly outof their locking relationship between sleeves 25 and 34. Continuingexpansion of the gases generated by the explosion of cartridge 21 willact against the left hand of housing 36, urging the Whole of internalcylinder 17 to the left whereby forcible ejection of piston 18 isachieved. It is to be noted that as the right end of sleeve 34 passescollar 26 a port 43 of collar 26 is uncovered and the ex- 4asaeftortserve an auxiliary purpose in providing a source of pneumatic pressuresubstantially simultaneous with the actuation or release of canopy 13.

Piston 18, which is normally the movable member during opening and,closing of canopy 13, is formed in a reduced diameter'middle portion 44which is integral at its right end with skirt 3 8, and which isthreadably secured at its left en-d to clevis element 23. A plurality ofsealing rings 45 are provided to effect a sealing relation between thecomponents of piston 18 and between piston 18 and internal cylinder 17.

End portion 33 of internal cylinder 17 is provided with a port 46 foradmitting lluid pressure to' an annular chamber 47 formed between sleeveelement 25 of internal cylinder 17 and middle portion 44 of piston 18whereby piston 18 may be driven inwardly or to the right, as viewed inFigure 2. Similarly, as seen iu Figure 4, clevis 23 is provided with anintegral port 48 for admitting iluid pressure to the hollow interior ofpisto'n 18 whereby piston 18 may be urged outwardly or to the left, theaction of Huid pressure within piston 18 being such as to oppose theaction of the lluid pressure within annular chamber 47. It will beapparent that by adjusting the effective pressure areas against whichthe pressure acts in chamber 47 and in piston 18, the weight of canopy13 urging piston 18 inwardly may be balanced. In. this event there maybe used a common source of fluid pressure for both ports 46 and 48,although it is also apparent that the amount of pressure admitted toeither port 46 or 48 may be adjusted so that regardless of the effectivepressure areas the canopy 13 is properly counterbalanced or, for thatmatter,'urged in one direction apprecably more than inanother'directiorn A second embodiment of the present invention, hereingenerally referred to as device 49, Figure 5, is essentially similar todevice 11 just described, except that the portions of device 11 whichutilize dilerential pressures for counterbalancing are replaced by ahelical spring 51 whose spring constant may be chosen to' afford thedesired counterbalancing action for canopy 13.

Actuating device 49 comprises generally an outer cylinder or body 52,which is pivotally mounted to fuselage 12 at a depending ear orprojection 53. Body 52 includes a middle or sleeve portion 54 which isthreadably secured at its lo'wer end, as viewed in Figure 5, to a baseportion 55 which serves to close the lower end of body 52 and which isformed to dene a central and axially extending cylinder element 56 openat its upper end and provided with a bore 57 through its closed end.

, An internal cylinder 58 is carried within sleeve portion 54 of body 52in locked relationship therewith by reason of the disposition of a shearpin 59 through normally aligned openings (not shown) in internalcylinder 58 and body 52. Itis noted, however, that internal cylinder 58is adapted for slidable axial movement within sleeve portion 54 in theabsence o'f the restraining influence of pin 59. Internal cylinder 58includes a sleeve 61 adapted for slidable cooperation with sleeveportion 54 in the event just described, and also includes a base portion62 threadably secured to the lower end of sleeve 61 and normally restingupon the upper edge of the wall of cylinder element 56, base portion 62being provided with a central aperture which in effect forms acontinuation of the internal surface of cylinder element 56. Between thelower panding gases are permitted in part to pass through port 43..- Bythis means actuating device 11 is also adapted to portion of sleeve 61and base portion 62 there is rigidly held a peripheral foot or llange 63of an axially extending cartridge holder 64. Also, a cartridge 65 isnested within holder 64 and includes a peripheral ange which is rigidlyheld between ange 63 of holder 64 and base portion 62 of cylinder 58. Itwill be apparent that there is thus formed an integral assembly ofcylinder 58, cartridge holder 64 and cartridge 65, each of whichcomponents is immovable relative to each other, and normally immovablewith respect to outer body 52.

Slidable within the interior of cylinder element 56 and Qta-*Legeinbore:57"of bodyl SZis a firing pin 66.which.isfbiasedinupwarddirectioniby af helieal'springf 67 housed within an Internal boreof firing pin Pin 66, howevenrisno# mally `restrained against upwardmovement by reason" of theef projection of'shear pin 59 through thewalllof ele:- irientg-S'Gand into an annular groove 6,'8 provided intheperiphery of firing pinoli, as illustrated;

Mountedto base portion fiisan extractorfassembl'y r69 which embodies apiston (not shown) secured to-pin 59a and slidablegoutwardly upontherintroduction` of'` lluid pressure into assembly 69 througha-conduit-71, as illustrated. This movementrof the=piston and' ofassembly/6:9 moves shear. pin 59 out ofi annular groove 68 off''ri'ngpin 66, and spring 673drives firing pin 66 ujgiwardlyv against eartridge65'.' The expanding'V gasesof exploded cartridge 651 will then drivecartridge holder 64 and internal'cylinder. 58V upwardly, shearing pin5,9 inthe process.` The operation justv described is thusleifectiveftoraise canopy 13v1andf`fseparate it fro'm fuselage l N12".y

Normal manual opening and closingof"canopy1'3"is assisted l'by actuatingdevice 49 through the-counterbal aneingfetfect of an internal --pistony72, which piston 72 includes :a skirt section 73 `axially slidablewithininternal cylinderSS; anupper wall'74; and a'clevis member 75 whichispifvotally mounted-to canopy 13. Skirtsection 731' and upperfwall 74form an'ienclosure for spring 51v and fit will be apparent thattheaction of-spring 51 against wall741will tendtoextendpiston 72 out of`cylinder 58,' therebyraising canopy 13.` In this-manner the'action ofspring-.5144 serves'to counterbalance ythe weight of canopy 13,1 andthebias Vof spring 51 islpreferably chosen suchl thatv theweightfof'canopylla' is just balanced.'

A latchlassembly 76," carried Lat they upper end of cylinderSS, includesa springbias. latch element 77, which passes `through an opening in the'upper end of cylinder 58, andwhic'h serves to'fmaintain the canopy in`raised or -lowered position by engagement of element 77'with latchholes'78' and 79, respectively, provided in skirt section'73 ofinternalpiston 72.

A port 81, similar toport 43 ofthe iirst embodiment, isfprovidedinbody52 and serves during the ejectiony operation to vent a portion of theexpanding gases of cartridge 65, thereby providing a source of pneumaticpressure'substantially simultaneous with the ejectionV of canopy 13Asince -gases cannot pass through port Sluuntil internal cylinder 58"haspassedlbeyond'port 81.V

From-the above it will be apparent that the present invention providesan actuating device which is effective to provide -a counterbalancingactiony during normal operation of a movable element such as an-aircraft canopy, and which is operativelin an emergency to effect quickand forcible movement of `suchmovable element when desired. Thiscombination of functions and structure within `one device produces acompact and lightweight structure relatively simple in construction andwhich is reliablefinV operation.

Whilewcertain preferred embodiments of the invention have beenspeciically disclosed, it is understood that the invention is notlimited thereto as many variations will be readily apparent to thoseskilled in the art and the invention is to be given its broadestpossible interpretation within the terms of the following claims:

What I claim is:

l. An actuating device adapted for interconnection between a fixedstructure and a movable structure which is movably mounted to said fixedstructure, said device comprising a cylindrical housing having an openend and adapted for connection to said xed structure, a

cylinder member carried within and capable of sliding movement out ofthe open end of said housing, locking means operative to normallyprevent said sliding movement of said cylinder member and adapted to berendered inoperative to thereby permit said sliding movement, a

pistongelement slidably carried and normally freely `reciprocable withinsaid cylinder member and adapted for connection tof saidf: movable`structurer whereby re cip'rocable movement of saidl` pistonelementetici-,ts normal movement of said movablestructur'e; said` pistonelement being movable by saidcylinder'member upon sliding movement ofsaid cylinder Vmember in Iani emergency, arid ejection ineaii's carriedwithin s'id housing and` including ay cartridge source of pressurizedgases carriedf`witl1in said cylinder member andislidably-posi tionedadjacent said locking 'meansfor' holding said lock ingmeans in operativeposition, anda ring pinV actuable in an emergency for striking saidcartridge source to releasefsaid gases and move s-aid cartridge sourceslidably out of adjacency with said locking means-to render'said lockingvmeans inoperative and effect said slidable movement ofsaid.l cylindermember relative to said housing whereby thereoccurs emergency movementof said piston element and consequent emergency movement of said movablestructure.

Z; actuatingfdevi'ce adapted forY interconnection be-l tweenia ixedstructure and a movable structure which is=pivotally mounted'to saidixed'structure for movement toward and awayffrom s-aid xed structure,said device comprisinga cylindrical housing having an open end andadapted=for connection to said' fixed structure, a cylinder membercarried within and capable of sliding movement out ofthe open endlofsaid housing,l locking means. operativer'to normallyl prevent saidsliding movement Vof said cylinder `member and adapted to'berenderedinoperative to therebyrpermit said sliding movement, a`piston element slidably'carried and normally freely reciprocable withinsaid cylinder'member and adapted-for connection to said movablestructure whereby reciprocable movement of saidpiston elementeiectsnormal-pivotal movement of said movable structure toward and awayfrom said fixed structure,- said piston element being engageable formovement by said cylinder `member lupon sliding movement of said'lcylinder memberv in an emergency, and ejection means-carried within saidhousing and including Aav cartridge` source of pressurized gases carriedwithin said cylinder member and slidably positioned adjacent .said`locking means for holding said locking means in opera-` tive position,said ejection means also includingV afiring pinaxially slidable withinsaid cylindrical housinglland actuable in an emergencyv for vstrikingsaid, cartridge source'to effect release of said gasesfand movesaidcar-- tridge'souree slidably out of adjacency fwithsai'd locking meansto render said locking means:inoperative'andelect said slidablemovementof said cylinder-member relative to said housing whereby thereoccurs emergency moveV ment "of said piston element and `consequentemergency movement of' said movable structure.

3. An actuatingdev-ice adapted forinterconnee'tionbesl tween afxed'structure and 'a movable structure whi'chfisv pivotally mounted-tosaid Xedlstructure, saidldevice comprising'a cylindrical housing havingan open end and adapted for connection to said fixed structure, acylinder member fcarried withinand'capable of `sliding movement out oftheopen end of said housing,locking1means opera# tive to normallyprevent said sliding movement of said cylinder member and adapted formovement to inoperative position to thereby permit said slidingmovement, a piston element slidably carried within said cylinder memberand adapted for connection to said movable structure whereby movement ofsaid piston element effects normal pivotal movement of said movablestructure, said piston element being engageable for movement by saidcylinder member upon sliding movement of said cylinder 'member in anemergency, a cartridge holder carried within said cylinder member andslidably positioned adjacent said locking means for holding said lockingmeans in operative position, a cartridge in said cartridge holder, saidcartridge being a source of pressurized gases, and a firing pin actuablein an emergency for striking said cartridge to release said gaseswhereby said cartridge holder is slidably moved out of adjacency withsaid locking means to; permit said locking means to move to inoperativeposition, said slidable movement of said cylinder'member relative tosaid housing being veffected thereby to cause emergency movement of saidpiston element and consequent emergency movement of said movablestructure. .j .4. An actuating device for a tirst element which ismovably mounted upon a second element, saiddevice comprising a housinghaving an open end and connected to said second element, a cylindermember carried within and capable of sliding movement out of the openendof said housing,v a plurality of ball elements carried in normallyaligned openings provided in said cylinder member and said housing tonormally prevent sliding movement therebetween, said ball elements beingadapted for movement out of said openings to thereby permit said slidingmovement, a piston element slidably carried withln said cylinder memberand connected to said first element whereby movement of said pistonelement effects normal pivotal movement of said second element, saidpiston element being engageable for movement by said cylinder memberupon sliding movement of said cylinder member in an emergency, andejection means carried within said housing and including a cartridgesource of pressurized gases carried within said cylinder member andslidably positioned adjacent lsaid ball elements for -holding said ballelements in said openings, and a tiring pin actuable in an emergency forstriking said cartridge source to release said gases and move saidcartridge source slidably out of adjacency with said ball elements toeffect movement of said ball elements out of said openings and alsoeffect said slidable movement of said cylinder member relative to saidhousing whereby there occurs emergency movement of said piston elementand consequent emergency movement of said first element.

5. An actuating device adapted for interconnection between a xedstructure and a movable structure which is pivotally mounted to said xedstructure, said device comprising a cylindrical housing having an openend and adapted for connection to said fixed structure, a cylindermember carried within and capable of sliding movement out of the openend of said housing, said cylinder member including an integral andinternally located sleeve portion closed at one end, locking meansoperative to normally prevent said sliding movement of said cylindermember and adapted for movement to inoperative position to therebypermit said sliding movement, a piston element slidably carried withinsaid cylinder member and adapted for connection to said movablestructure whereby movement of said piston element effects normal pivotalmovement of said movable structure, said piston element being engageablefor movement by said sleeve portion of said cylinder member upon slidingmovement of said cylinder member in an emergency, said piston elementforming an annular chamber with said cylinder member, and forming aninternal chamber with said sleeve portion of said cylinder member, saidpiston element `being ported to admit uid pressure into said annularchamber and said internal chamber whereby forces acting to move saidpistonfel'ement may be counterbalanced, a cartridge holder carriedwithin said sleeve portion of said cylinder member and slidablypositioned adjacent said locking means for holding said locking means inoperative position, a cartridge in said cartridge holder, said cartridgebeing a source of pressurized gases, and a tiring pin actuable in anemergencyv for striking said cartridge to release said gases wherebysaid cartridge holder is slidably moved out of adjacency with saidlocking means to permit said locking means to move to inoperativeposition, said slidable movement of said cylinder member relative tosaid housing being eiected thereby to cause emergency movement of saidpiston element and consequent emergency movement of said movablestructure.

6; An actuating device interconnected between an aircraft fuselage and acanopy pivotally mounted to said fuselage and adapted'to be released byfluid pressure, said device comprising a cylindrical housing connectedto the aircraft fuselage, said housing having an open end and auidpressure port in a wall thereof, a cylinder member carried Within andcapable of sliding movement out of the open end of said housing, lockingmeans operative to normally prevent said sliding movement of saidcylinder member and adapted for movement to inoperative position tothereby permit said sliding movement, a piston element slidably carriedwithin said cylinder member and connected to said aircraft canopywhereby movement of said piston element eiects normal pivotal movementof said aircraft canopy, said piston element being engageable formovement by said cylinder member upon sliding movement of said cylindermember for jettisoning said aircraft canopy, a cartridge holder carriedwithin said cylinder member and slidably positioned adjacent saidlocking means for holding said locking means in operative position, anexplosive cartridge in said cartridge holder, said cartridge being asource of pressurized gases, and a tiring pin piston actuable formovement to strike said explosive cartridge to release said `gaseswhereby said cartridge holder is slidably moved out of adjacency withsaid locking means to permit said locking means to move to inoperativeposition, said slidable movement of said cylinder member relative tosaid housing being elected thereby to cause movement of said pistonelement and consequent jettisoning of said aircraft canopy, said iluidpressure port of said housing being uncovered during said slidablemovement thereby permitting a portion of said pressurized gases toescape and provide said uid pressure, whereby initiation of release ofsaid canopy may be had substantially simultaneously with the exit ofsaid cylinder member from said housing.

References Cited in vthe `tile of this patent UNITED STATES PATENTSMartin Feb. 28, 1956

